/*
 * ------------------------------------------------------------------------
 *  Copyright by KNIME AG, Zurich, Switzerland
 *  Website: http://www.knime.com; Email: contact@knime.com
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License, Version 3, as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses>.
 *
 *  Additional permission under GNU GPL version 3 section 7:
 *
 *  KNIME interoperates with ECLIPSE solely via ECLIPSE's plug-in APIs.
 *  Hence, KNIME and ECLIPSE are both independent programs and are not
 *  derived from each other. Should, however, the interpretation of the
 *  GNU GPL Version 3 ("License") under any applicable laws result in
 *  KNIME and ECLIPSE being a combined program, KNIME AG herewith grants
 *  you the additional permission to use and propagate KNIME together with
 *  ECLIPSE with only the license terms in place for ECLIPSE applying to
 *  ECLIPSE and the GNU GPL Version 3 applying for KNIME, provided the
 *  license terms of ECLIPSE themselves allow for the respective use and
 *  propagation of ECLIPSE together with KNIME.
 *
 *  Additional permission relating to nodes for KNIME that extend the Node
 *  Extension (and in particular that are based on subclasses of NodeModel,
 *  NodeDialog, and NodeView) and that only interoperate with KNIME through
 *  standard APIs ("Nodes"):
 *  Nodes are deemed to be separate and independent programs and to not be
 *  covered works.  Notwithstanding anything to the contrary in the
 *  License, the License does not apply to Nodes, you are not required to
 *  license Nodes under the License, and you are granted a license to
 *  prepare and propagate Nodes, in each case even if such Nodes are
 *  propagated with or for interoperation with KNIME.  The owner of a Node
 *  may freely choose the license terms applicable to such Node, including
 *  when such Node is propagated with or for interoperation with KNIME.
 * ------------------------------------------------------------------------
 */
package org.slf4j.impl;

import java.util.HashMap;
import java.util.Map;
import java.util.Objects;

import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.LogManager;
import org.knime.core.node.NodeLogger;
import org.slf4j.ILoggerFactory;
import org.slf4j.Logger;
import org.slf4j.helpers.NOPLogger;

/**
 * A copy of org.slf4j.impl.Log4jLoggerFactory.class, adjusted to delegate to {@link NodeLogger}. Additional references
 * to the source are provided in this package's description or the accompanying LICENSE.txt.
 *
 * @author Bernd Wiswedel, KNIME GmbH, Konstanz, Germany
 */
public class NodeLoggerLoggerFactory implements ILoggerFactory {

    // key: name (String), value: a Log4jLoggerAdapter;
    Map<String, Logger> loggerMap;

    public NodeLoggerLoggerFactory() {
        loggerMap = new HashMap<>();
    }

    /*
     * (non-Javadoc)
     *
     * @see org.slf4j.ILoggerFactory#getLogger(java.lang.String)
     */
    @Override
    public Logger getLogger(final String name) {
        Logger slf4jLogger = null;
        // protect against concurrent access of loggerMap
        synchronized (this) {
            slf4jLogger = loggerMap.get(name);
            if (slf4jLogger == null) {
                // for a name such as "foo.bar.SomeName" check if Log4J contains any configured loggers
                // (check "foo.bar.SomeName", then "foo.bar", then "foo")

                // known loggers (org.knime) are passed through, unknown loggers (e.g. org.apache.arrow.xyz) are noop'ed
                // see log4j.xml -- it contains separate loggers for {com|org}.knime
                String currentNamePrefix = name;
                boolean isNameOrPackageKnownToLog4j = false;
                while (!isNameOrPackageKnownToLog4j) {
                    isNameOrPackageKnownToLog4j |= LogManager.exists(currentNamePrefix) != null;
                    String nextSubstring = StringUtils.substringBeforeLast(currentNamePrefix, ".");
                    if (Objects.equals(currentNamePrefix, nextSubstring)) {
                        break;
                    } else {
                        currentNamePrefix = nextSubstring;
                    }
                }
                if (isNameOrPackageKnownToLog4j) {
                    NodeLogger logger = NodeLogger.getLogger(name);
                    slf4jLogger = new NodeLoggerLoggerAdapter(name, logger);
                } else {
                    slf4jLogger = NOPLogger.NOP_LOGGER;
                }
                loggerMap.put(name, slf4jLogger);
            }
        }
        return slf4jLogger;
    }
}
